note moritz <blockquote>Why does the block use $^a in one place (the automatic parameter) and $a in another place? Shouldn't that be a different (undeclared) variable? (Likewise for b).</blockquote> <p>No, the <c>^</c> twigil is only necessary in the first occurrence. That was introduced because things like this: <code> my $block = { my $v = %hash{$^key}; say "The lookup {%hash{$^key}} yields $v"; }; </code> <p>Would complain about the closure inside the string getting no argument, because <c>$^key</c> was interpreted as a formal parameter to the inner-most closure, which in this case was the one inside the string. <p>Or more general, you couldn't refer to outer lexicals that happened to be self-declaring formal parameters. <p>So it was decided that after <c>$^foo</c> occurred once, you could refer to it as <c>$foo</c> to, disambiguating it in inner blocks. 771219 772560